THC FAQs

What is THC Norm?

One recurring question we get is is how determine abstinence versus relapse in chronic marijuana users who start a treatment program with positive marijuana results. Creatinine normalization (THC Norm) of marijuana levels obtained during urine screening is one tool we use to help distinguish between residual positive results and positive results due to renewed use. This practice is especially important for accurate results interpretation when comparing successive samples from the same individual.

Another common concern with regards to marijuana use is the length of detection. Marijuana, in general has a longer period of elimination than all of the other drugs that we test for. With chronic marijuana users, there can be a significantly long elimination phase. This is due to the fact that cannabinoids, the psychoactive compounds in marijuana, are highly lipid soluble and repeated use of the drug will cause storage of the molecules in the body’s fatty tissues. There are many theories and myths surrounding the question "how long does marijuana stay in your system for?". In studies of chronic marijuana users, detection times at common cut-off levels range from 30-70 days. Recreational or casual users of marijuana can have detectable levels in their urine for 3-10 days. We have found the following graph, obtained from Kouri et al (1999), to be very useful in understanding marijuana elimination in chronic marijuana users.